In the hydrocarbon industry, it is common for a multiphase mixture comprising a gas phase and a liquid phase to be produced from a wellbore and/or to be transported through pipelines during or after production. In general, the gas phase may comprise gaseous hydrocarbons and the liquid phase may comprise oil and water. Furthermore, it is often important in the hydrocarbon industry to measure the flow properties of the components of the multiphase mixtures, including making measurements regarding the amount of the gaseous hydrocarbons in the multiphase mixture, the amount of the liquid hydrocarbons and/or water in the multiphase mixture and/or to measure the velocity of the gaseous hydrocarbons, liquid hydrocarbons and/or water in the multiphase mixture so that flow rates for the phases or components of the phases may be determined.
With the growing importance of natural gas, there exists a need in the hydrocarbon industry for an accurate determination of gas and liquid (oil and water) flow rates for wet-gas flows. Wet gas flows may be considered to comprise multiphase mixtures with a gas-volume-fraction (“GVF”) or gas-cut greater than 90% or more particularly a GVF beyond 95%. Often a wet gas flow, as is often encountered in gas condensate systems, may comprise an extremely high amount of gas, i.e., the wet gas flow may have a gas cut that is 90% or may be greater than 99%. Generally, making accurate measurements of a wet-gas flow using a single-phase gas flowmeter may be difficult. Moreover, existing commercial multiphase flowmeters may deliver good performance at gas-cuts below around 95%, but may not perform well for higher gas-cut percentages. As such, to increase the gas-cut range of the multiphase flowmeter beyond 95%, some multiphase flowmeters use complicated procedures such as partial gas separation and/or flow diversion devices.